The present invention relates to a guard for a filament-type trimmer and, more particularly, to a guard for a filament-type trimmer for protecting saplings and other structures not to be trimmed while simultaneously trimming grass, weeds, and other vegetation that is to be at least partially trimmed.
Various types of devices have been proposed for many years to facilitate the removal of vegetation by mowing, trimming, edging and like operations. In general, these devices have employed a metal blade to effect vegetation removal.
There are various forms of “filament-type trimmers” used for the purpose of trimming “vegetation.” The term “filament-type trimmers” will be used herein to describe products including, but not limited to, flail-type cutters, flail trimmers, string trimmers, cord-type cutting device, and other means for trimming as well as products known as Weed-Whackers™, Weed-Wackers™, Weed Eaters™, Weed Whips™, Weed Crashers™, and Weed Wonders™. The term “trimming” will be used herein to describe processes such as cutting, edging, cultivation, and other trimming processes. The term “vegetation” will be used herein to describe grass, weeds, ground covering, blackberries, and other types of vegetation.
Filament-type trimmers generally include a head assembly substantially at a first end of an extension member and a handle assembly (for one or two handed operation) substantially at a second end of the extension member. An activator (e.g. a switch) for selectively applying power to the filament-type trimmer may be positioned, for example, on the handle assembly or the extension member. The head assembly includes a rotatable head with at least one non-rigid filament (e.g. a flexible cutting line, radial strands, string) that extends generally radially outwardly. The filament-type trimmers trim by means of the filament that extends generally radially outwardly from the rotatable head when the rotatable head rotates at high speeds. Filament-type trimmers work because the filaments rotate at high speed under which they assume a tensioned condition due to centrifugal force. It has been found that these filaments can be used to cut grass and other delicate vegetation more safely and with a greater degree of flexibility than devices using rotating rigid blades.
The head assembly in some known systems includes means for protecting the operator of the filament-type trimmer. For example, in U.S. Pat. No. 4,161,820, the housing includes a rearwardly-extending tail part which serves as a protection to the user to prevent inadvertent contact with the rotating cutting line. Another example is U.S. Pat. No. 5,644,844, in which a semi-circular shield is carried on the rear half of lower flange to protect the operator from flying debris. The disclosures of these references are incorporated by reference herein.
U.S. Pat. No. 5,010,720 discloses a semi-circle guard of tempered aluminum rod stock that is positioned to have a forwardmost arcuate portion in relation to a trimmer. The guard works in combination with a shield (that is part of the original trimmer). The guard and guide assembly can be used while trimming around stationary structures such as walls, large rocks, grave markers and the like to preclude contact of the stationary structure by the filament segment, thus preventing marring of the structure and wear of the filament segment. There are several problems with the guard of the device disclosed in this reference. First, even in the shown embodiment, there is a gap on both sides of the trimmer where the guard meets the shield. Gaps in the sides are particularly troublesome because the standard operation of a trimmer is a side-to-side motion. Second, some trimmers have smaller shields and/or no shields. The disclosure of this reference is incorporated by reference herein.
U.S. Pat. No. 4,501,332 is directed to a hand carried portable weeder convertible to a cultivator apparatus. In one embodiment, the standard guard is removed and replaced with a weeder/cultivator element for the string head of the apparatus. The weeder/cultivator element includes an inverted dish-shaped element. There are several problems with the guard of the device disclosed in this reference. For example, because the dish-shaped element is solid, it would limit how low the non-rigid filament(s) could cut. Further, because the dish-shaped element is solid, it would block visibility thereunder, despite the statements set forth in the reference. Still further, the peripheral edge of the dish-shaped element appears to be below the level of the non-rigid filament(s) such that the peripheral edge would push the vegetation down and make it impossible to get a good cut. The disclosure of this reference is incorporated by reference herein.
U.S. Pat. No. 4,890,389 is directed to a guard for a power trimming device. The guard partially encloses the rotating cutting element as a housing is formed from a rigid bar having a generally circular configuration with an open front portion formed by outwardly flared ends. This reference discloses that the guard can be secured to the conventionally existing cutter housing of a trimming device using (in one embodiment) a compound adjustable bracket. There are several problems with the guard of the device disclosed in this reference. For example, there is no forward protection as the front portion is open. Another example is that the guard appears to be below the level of the non-rigid filament(s) so that the guard would push the vegetation down and make it impossible to get a good cut. The disclosure of this reference is incorporated by reference herein.
U.S. Pat. No. 4,118,865 is directed to a grass trimmer that includes a shroud 30 integrally formed with the housing of the grass trimmer. The shroud partially surrounds the hub member and cutting line to control the direction in which grass clippings or other objects engaged by the spinning line are projected. To emphasize, the shroud must be partial or it would not direct the grass clippings. The disclosure of this reference is incorporated by reference herein.
U.S. Pat. No. 3,831,278 is directed to a grass trimmer that includes a solid disc shield. In one embodiment the disc shield is provided with a peripheral flange or leg of limited height and size as a guide for edging close to fixed objects and as a spacer for the slicing elements above the ground. The reference specifies, however, that the apparatus may safely be used without a disc shield if desired. There are several problems with the guard of the device disclosed in this reference. For example, because the disc shield is solid, it would limit how low the non-rigid filament(s) could cut. Further, because the disc shield is solid, it would block visibility thereunder. Still further, because the disc shield is solid, there is a problem with debris collecting under the solid disc shield and interfering with the non-rigid filament(s). The disclosure of this reference is incorporated by reference herein.
U.S. Pat. No. 4,189,901 is directed to a flail shredder that has an assembly that can be adjustably moved between positions in relation to the ground. The flail shredder includes a circular guide wheel indicated that is concentrically mounted on the flange of a second bearing assembly (which is coaxially mounted on the drive shaft). The circular guide wheel includes an imperforate circular shield and a resilient tubular rim. There are several problems with the guard of the device disclosed in this reference. For example, because the circular shield is imperforate, it would limit how low the non-rigid filament(s) could cut. Further, because the circular shield is imperforate, it would block visibility thereunder. The disclosure of this reference is incorporated by reference herein.
U.S. Pat. No. 5,115,870 is directed to a flexible flail trimmer for conventional trimming of grass, weeds, and the like, and for edging of sidewalks has a combined guide and guard rotatably mounted inboard of the trimmer cutting head. There are several problems with the guard of the device disclosed in this reference. For example, because the combined guide and guard is solid, it would limit how low the non-rigid filament(s) could cut. Further, because the combined guide and guard is solid, it would block visibility thereunder, despite the statements set forth in the reference. U.S. Pat. No. 5,023,998 discloses a housing or deck, which despite the small vents therethrough, would have similar problems as well as other problems. The disclosure of this reference is incorporated by reference herein.